This invention relates to a frequency modulation detector.
A previously-proposed pulse count FM detector produces an FM detection output in such a way that a frequency (FM) signal turned into a pulse train by an FM limiter is converted into a train of pulses having a predetermined pulse width every period (single) or every half period (double), by a monostable multivibrator (pulse width modulation), and that the train of pulses is passed through a low-pass filter.
Such a detection system has the disadvantage that, since the pulse train generated by the pulse width modulation is a binary pulse signal, high-frequency components and carrier components contained therein are liable to appear at the output of the low-pass filter, resulting in an inferior S/N (signal-to-noise) ratio of the FM detection output.